The assembly of the divisome in E. coli occurs in two temporally distinct steps. In the first step, which is under spatial regulation, polymers of FtsZ ae attached to the membrane with the aid of FtsA and ZipA to form the Z ring. Additional nonessential FtsZ interacting proteins also join the Z ring at this time and contribute to the integrity of the Z ring. In a second step, seven additional essential proteins are added nearly simultaneously to form the divisome that divides the cell. In this grant we will focus on three aspects of the regulation of bacterial cell division. In the first aim we will test our Tarzan of te Jungle model for Min oscillation that contributes to the spatial regulation of the Z ring. In the second aim we will test our model for how FtsA is regulated to recruit late division proteins to the Z ring. This model proposes that FtsA's ability to recruit downstream division proteins to the Z ring is determined by its oligomeric state, which is regulated by the dynamics of proteins that interact with the conserved carboxy tail of FtsZ. Lastly, we will examine how a novel regulator, which we think represents a new regulatory aspect of FtsZ, affects FtsZ activity.